This project proposes to study the use of cadaveric fresh frozen bone and osteoarticular allografts in the treatment of non-immunosuppressed patients with malignant and aggressive bone tumors following local wide resection of the lesion. Thus far 73 patients have been treated by this technique and followed periodically by X-rays, bone scans, and chemical and immunologic analyses to assess rates of healing at the anastomosis site, rate of incorporation of the bone and evidences of "rejection" as a result of antibody development. In addition, laboratory studies will be performed to improve methods of cryopreservation of the articular cartilage portion of the segments and evolve improved techniques of banking. A cat model has been devised which simulates the human procedure and which will be used to assess the value of short-term corticosteroids, azothiopurine and multiple small blood transfusions in improving the graft response. A rabbit model has been developed to study the use of microvascular anastomosis techniques to provide a free vascularized orthotopic auto- and allografts and assess the pattern of incorporation and the viability of the bone, articular and epiphyseal cartilage by metabolic and radioisotopic tracer techniques.